The event was supposed to take place at 2 p.m. on Thursday, September 10.
The presidential office blamed the Russian occupants.
"Just like we expected, representatives of the illegal armed formations in the occupied Donbas did not expect Ukraine's constructive approach. Their belief in their own propaganda and divorcement from reality keep them away from an adequate assessment of the ongoing events. As of today's morning, we received a number of demands from them; these contradict each other, distort the nature of agreements about the ceasefire and humiliate the OSCE even more as authoritative and objective mediator. This is why the single inspection of one particular poin, which was agreed within the session of the security subgroup of the Trilateral Contact Group, will not take place - due to permanent change of requests by the Russian side", reads the message.